Properties of protein based biodegradable polymer film
Nabanita Saha, Vladimir Pavlinek, Martin Zatloukal, Petr Saha
Polymer Cenre,Faculty of Technology, Tomas Bata University in Zlin
Czech Republic
Keywords: Protein hydrolysate(HP), Biodegradable polymer films, mLLDPE/HP blends
Environment-friendly biodegradable polymer films are prepared to reduce the pollution load of plastics. Metallocene based linear low-density polyethylene (mLLDPE) is a general-purpose synthetic polymer, was modified with protein hydrolysate (HP) which shows better performance in biodegradation by Aspergillus oryzae (F-172) under controlled laboratory conditions. HP is a natural biopolymer, isolated from chrome-tanned solid leather waste of tanning industry by enzymatic hydrolysis. Though modified polymer film of mLLDPE has shown better results from biodegradable point of view it is required to study their basic properties like morphology, physical, thermal, mechanical and rheological behaviour before commercial application of the film as biodegradable polymer film.
It was observed that film of pure mLLDPE is transparent but after blending with HP the colour of modified polymer film of 10 %HP, 20 % HP and 40%HP are changed into pale white to light yellow. Both optical and scanning electron microscopic views show that the compatibility between mLLDPE and HP is quite good. The ATR-FTIR spectra of pure and blended films indicate that individual physical structure of mLLDPE and HP does not change, due to blending even no new functional group has been developed. Similarly, thermal properties of mLLDPE do not effect much due to polymer modification with HP. The mechanical properties of pure mLLDPE and mLLDPE/HP blend polymer films decreased with the increase in concentration of HP. Significant reduction of mechanical properties occurs at concentration higher than 20% HP in the pure mLLDPE but complex viscosity of the protein based mLLDPE polymer film is increased with the increase of concentration HP. mLLDPE film with 10% HP does not effect much in melt flow behaviour of modified polymer.
The protein based biodegradable polyamidic polymer film with 20 % HP in mLLDPE is the optimal composition from mechanical strength property and biodegradable point of view